Circuit interrupter trip device

ABSTRACT

A circuit interrupter trip device responsive to abnormal currents in conductors of an electrical distribution system characterized by a circuit breaker within a first insulating housing and having a mechanism for opening and closing separable contacts which mechanism comprises a releasable member movable from latched to unlatched positions, trip means comprising a stationary magnetic structure for each conductor as well as a coil and core assembly and armature therefor, a trip bar movable to unlatch the circuit breaker mechanism and biased in the latched positions, and a manually operable trip pin for moving the trip bar to the unlatched position.

United States Patent [191 Salvati [4 Apr. 23, 1974 CIRCUIT INTERRUPT ERTRIP DEVICE Prima ExaminerHarold Broome 1 t: 0h G.SltB Fll,P. [75] menor J n a ya eaver a s a Attorney, Agent, or Firm-L. P. Johns [73]Assignee: Westinghouse Electric Corporation,

Pittsburgh, Pa. [57] ABSTRACT [22] Filed: 1973 A circuit interruptertrip device responsive to abnor- [21 1 App], 352 824 mal currents inconductors of an electrical distribution system characterized by acircuit breaker within a first insulating housing and having a mechanismfor open- [5? US. Cl.., 335/176, 335/42 ing and closing separablecontacts which mechanism [5 git. C]. H0! 9/09 comprises a releasablememberv movable from latched [58] of Search 335/176 to unlatchedpositions, trip means comprising a sta- 200/166 M tionary magneticstructure for each conductor as well 56 R f as a coil and core assemblyand armature therefor, 21 1 e erences trip bar movable to unlatch thecircuit breaker mecha- UNITED STATES PATENTS nism and biased in thelatched positions, anda manu- 3,073,925 1/1963 Thomas et al. 335 42 allyoperable trip pin for moving the trip bar to the un- 3,260,822 7/1966Stephenson et al 335/42 latched position. 3,505,626 4/1970 Shaffer335/42 3,617,671 11/1971 Gleeson 200/166 M 7 Chums, 6 Drawing F s TOE W.h@ ||YuH Ell-l SHEET 1 IF 3 PATENTEMPR 23 m4 CIRCUIT INTERRUPTER TRIPDEVICE BACKGROUND OF THE INVENTION Field of the Invention This inventionpertains to a circuit interrupter and more particularly it pertains to amanually releasable pin for tripping the interrupter to the open circuitposition.

CROSS-REFERENCE TO RELATED APPLICATIONS This invention is related tothat disclosed in the application of Albert E. Maier and William J.Stephenson, Jr., Ser. No. 345,394, filed Mar. 27, 1973.

DESCRIPTION OF THE PRIOR ART Generally, circuit breakers that compriseovercur- SUMMARY OF THE INVENTION In accordance with this invention,there is provided a protective device for a circuit interrupter whichcomprises a stationary magnetic structure for each conductor of anelectrical distribution system and comprising a coil and core assemblyand an armature, a trip bar movable to effect tripping of the circuitbreaker mechanism and being biased in the latched position, a levermeans associated with each stationary magnetic structure for moving thetrip bar to the unlatched position, the lever means comprising thearmature and being movable in response to abnormal currents in at leastone of the conductors, the lever means also comprising a lever which isbiased away from the core assembly, means for adjusting the spacingbetween the lever and the core assembly, and a manually operable memberfor moving the trip bar to the tripped position.

The advantage of the device of this invention is that it provides for amore efficient unit.

BRIEF DESCRIPTION OF THE DRAWINGS DESCRIPTION OF THE PREFERREDEMBODIMENTS In FIG. 1, a circuit breaker is generally indicated at 3 andit comprises an insulating housing 5 and a circuit breaker mechanism7'supported within the housing.

The housing 5 comprises an insulating base 9 and an insulating coverll.v

The circuit breaker mechanism 7 comprises an operating mechanism 13, anda latch and trip device 15. Except for the latch and trip device, thecircuit breaker 3 is of the type that is generally described in thepatent to Albert R. Cellerini et al, U.S. Pat. No. 3,287,534 issued Nov.22, I966. The circuit breaker 3 is a threepole circuit breakercomprising three compartments disposed in side-by-side relationship. Thecenter pole compartment (FIG. 1) is separated from the two outer polecompartments by insulating barrier walls formed with the housing base 9and cover 11. The operating mechanism 13 is disposed in the center polecompartment and is a single operating mechanism for operating thecontacts of all three pole units.

Each pole unit comprises a stationary contact 21 that is fixedly securedto a rigid main conductor 23 that in turn is secured to the base 9 bybolt 25. In each pole unit, a movable contact 27 is welded or brazed toa contact arm 29 that is mounted on a switch arm 31 by a pivot pin 33.The arms 29 and 31 for all three of the pole units are supported at oneend thereof and rigidly connected on a common insulating tie bar 35 bywhich the arms of all three pole units move in unison. Each of thecontact arms 29 is biased about the associated pivot pin 33 by means ofa spring 37 to provide contact pressure in the closed position.

The operating mechanism 13 actuates the switch arms 31 between open andclosed positions. The mechanism comprises a pivoted formed operatinglever 39, a toggle comprising. two toggle links 41 and 43, overcentersprings 45and 47, and a pivoted releasable cradle or arm 49 controlledby the trip device 15. An insulating shield 51"for substantially closingan opening 53 in the cover 1 l, is mounted on the outer ends of theoperating lever 39 and has an integral handle portion 55 extending outthrough the opening to enable manual operation of the breaker. Thetoggle links 41 and 43 are pivotallyconnected together by a knee pivotpin 57. The toggle link 41 is pivotally connected to the releasable arm49 by a pin 59, and the toggle link 43 is pivotally connected to theswitch arm 31 of the center pole unit by a pin 61. The overcentersprings 45 and 47 are connected under tension between the knee pivot pin57 and the outer end of the operating lever 39. The circuit breaker ismanually operated to the open position by movement of the handle portion55 in a counterclockwise direction to the OFF position, which movementactuates the overcenter springs 45, 47 to collapse the toggle links 41and 43 to the position shown in FIG. 1, and opening movement of thecontact 7 arm 29 for all of the pole units in a manner well known in theart.

The circuit breaker is manually closed by reverse movement of the handleportion 55 from the OFF position to the ON position, which movementcauses the springs 45, 47.to move overcenter and straighten the togglelinks 41, 43 thereby movingthe contact arm 29, for all'of the poleunits, to the closed position as shown in broken line position.

The trip device 15 serves to effect automatic release of the releasablecradle or arm 49 and opening of the breaker contacts for all of the poleunits, in response to predetermined overload conditions in the circuitbreaker through any or all poleiunits of the circuit breaker, in amanner described hereinbelow.

The circuit through each pole unit extends from a right-hand terminal 63through the conductor 23, the contacts 21, 27, the contact arm 29, aflexible conductor 65, that is secured to the contact arm 29, aconductor 67, a trip conductor 69, to a left-hand terminal connector 71.Bolt means 73 secure one end of the trip conductor 69 to the conductor67 and the other end of the trip conductor 69 is disposed between abackup plate 75 and the terminal 71 where it is secured in place bymounting bolt 77 of the terminal 71.

As shown in FIGS. 2-6 the latch and trip device comprises a moldedinsulating housing base 81 and a molded insulating housing cover 79secured to the base to enclose a molded insulating trip bar 83 that iscommon to all three of the pole units. As shown in FIG. 3, the base 81includes a pair of spaced partitions 85 and 87 which are verticallydisposed and integral with the base for separating the interior of thehousing into three compartments, each compartment containing one of thethree poles. In a similar manner, the cover 79 is provided withpartitions corresponding to partitions 85 and 87 and have matingsurfaces therewith in a manner similar to the mating surfaces of theperipheral surfaces of the base 81 and cover 79 as indicated by aparting line 89 (FIG. 6).

As shown in FIG. 3, the partitions 85 and 87 have notches 91 and 93,respectively, which together with flat surfaces of the cover 79 serve asjournals for round shaft portions 95 and 97 of the trip bar 83.Accordingly, when the housing base 81 and cover 79 are assembled theyretain the trip bar 83 in place whereby the trip bar is free to rotateon an axis extending through the shaft portions 95 and 97. As shown moreparticularly, in FIG. 5, each section of the trip bar 83 located withinthe space compartments of the housing compriseupper and lower portions83a and 8312, which are above and below the axis of rotation of the tripbar. Each upper portion 83a is provided with an adjusting screw and nutassembly 99 which cooperates 'with a bimetal member 101 for adjustingthe spacing between the upper ends of the bimetal member and the tripbar portion 83a in response to the degree of deflection of the upper endof the member 101 toward the member 83a, whereby the trip bar 83 isrotated clockwise by the bimetal member and thereby trips the circuitbreaker to the open position. The lower end portion 83b of the trip bar83 is preferably provided with a drive screw 103 by which contact ismade with an adjoining member for similar rotation of the trip bar inthe manner to be described hereinbelow.

As shown more particularly in FIG. 5, the trip conductor 69 includes aninverted U-shaped intermediate portion 69a which constitutes a singleloop of a stationary magnetic structure. Stationary magnetic structurealso comprises a magnetic core 105, a U-shaped frame 107 having a pairof spaced flanges 109 one of which is shown in FIG. 5, and an armature 111. The assembly of the intermediate U-shaped portion 69a, the core 105,and the intermediate portion of the frame 107 together with the lowerportion of the bimetal member 101 are secured in place by suitable meanssuch as rivets 113 on the housing base'79. The lower end portion of thebimetal member 101 is in surface to surface contact with the conductor69 whereby upon the occurrence of a low persistent overload currentbelow a predetermined value of, for example, ten times normal ratedcurrent, the bimetal member 101 is heated ane deflects to the rightthrough an air gap dependent upon the setting of the adjustment screw99. Thus, when a low persistent overload current occurs, the trip bar 83is actuated to trip the circuit breaker.

The armature 111 is disposed between the space flanges 109 of theU-shaped frame 107 and is pivotally mounted therein to rotate about anaxis 115 near the lower end of the armature. For that purpose, thearmature 111 is preferably mounted by suitable means such as rivets 117on a support lever 119 having oppositely extending out-turned lugs 121which are seated in corresponding openings 123 in the flanges 109. Eachflange 109 is also provided with a V-shaped notch 125 into which edgeportions of the lever 1 19 and armature 111 extend. The notches 125thereby limit movement of the assembly of the lever 119 and armature 111when the armature is attracted toward the core 105. Accordingly, theassembly of the lever 119 and armature 111 which is biased in theclockwise direction by coil springs 127 (FIG. 3) is movablecounterclockwise against the springs to engage the drive screw 103 andthereby rotates the trip bar 83 clockwise. When an overload currentabove a value such, for example, as ten times normal rated current or ashort circuit current occurs, the stationary magnetic structure isenergized and the armature 1 1 1 is attracted toward the core 105causing instantaneous release of the releasable arm 49 and opening ofthe contacts 21 and 27.

In addition to the foregoing, means are provided for adjusting thespacing between the armature 111 and the core 105, whereby upon maximumspacing of the armature from the core, a greater current overload isrequired to attract the armature toward the core. Conversely, when thespacing is reduced, a smaller overload current is required to actuatethe trip bar 83. For that purpose a bracket 129 having a lower enddisposed over the upper end of the lever 119 is mounted within thehousing and is provided with calibration means including a calibrationscrew 131 at the upper end of the bracket 129. As shown in FIG. 3, eachbracket 129 includes a notch 133 on each opposite side thereof whichnotch is seated in corresponding projections 135 of the housing base 79where the brackets 129 are retained in place by the cover 81. Anadjusting knob 137 is seated within the top end of the housing base andis provided with a lower end portion having a cam surface. Inasmuch asthe bracket 129 is biased counterclockwise about its pivot by thesprings 127 of the lowerlever 1 19 the calibration screw 131 rides onthe cam surface of a lower portion 139 of the adjusting knob 137.

As shown in FIGS. 3 and 5, each adjusting knob 137 includes a flange141, the lower surface of which includes spaced notches 143. An indexmember is disposed below the flange 143 and is provided with aprojection 147 for engaging one of the spaced notches 143 as thecalibrating screw 137 is rotated to the desired position. Accordingly,the desired spacing between the armature 111 and the core 105 isestablished by rotation of the adjusting knob 137.

. Since the housing cover 79 is used to hold the bracket 129 in place,it is necessary to assemble the trip unit completely before calibratingthe position of the bracket 129. For that reason, a removable flexibleshield 149 is disposed in an access opening 151 of the cover 79 in orderto turn the calibrating screws 131 and 99. When the calibration is made,the shield 149 is replaced in the opening. The mechanism by which thereleasable arm 49 is released is shown in FIGS. 2, 4 and 6. Themechanism includes the trip bar 83, a trip lever 153 and a latch lever155. A U-shaped mounting frame 157 is mounted on the base 81 with spacedupright sides 157a and 157b providing mounting support for the levers.The trip lever 153 includes a U-shaped portion 159 at the lower endwhich portion is mounted on a pivot pin 161 which extends from the side157a of the frame. The U-shaped lower portion of the lever maintains thelever upright adjacent the frame side 157a. The upper end of the triplever 153 includes a flange 163 which engages a notch 165 on the tripbar 83. As shown in FIG. 4 a portion of the trip bar extends through anopening 167 in the insulating base 79.

The latch lever 155 includes down-turned portions 155a and 15512 whichare mounted on a pivot pin 169 the opposite ends of which are secured inthe sides 157a and 157b of the frame 157. A spring 171 is mounted on thepin 169 and has end portions engaging the levers 153 and 155 for biasingthe levers in the latched positions. When the releasable arm 49 is inthe latched position as shown in FIG. 1, the arm which is pivoted on apivot pin 173 is secured in the latched position below the lever 155 andapplies a rotatable force thereon. The latch lever 155 is prevented fromturning due to engagement of the lower end of the lever on a pin 175which is mounted in the U-shaped portion 159 of the trip lever 153. As aresult of the rotating force on the latch lever 155, the trip lever 153is biased clockwise and is prevented from movement by engagement of theflange 163 in the notch 165 of the trip bar 83. When the trip bar isrotated clockwise, the flange 163 is dislodged from the latch positionwithin the notch 165 and the trip lever 153 rotates clockwise to movethe pin 175 from engagement with the lower end of the latched lever 155,as a result the latch lever 155 is free to rotate about the pin 169 andthereby unlatch the releasable arm 49 from the latched position.

In accordance with this invention the circuit breaker 3 comprises meansfor manually tripping the breaker. The means includes a pushbutton orpin 177 which is disposed in a bore 179 of the adjusting knob 137. Acompression spring 181 is provided in the bore 179 to hold the pin 177in the non-trip or retracted position. As shown in FIG. 5 the lower endof the pin 177 has tapered or bevelled sides 183 and has a diametergreater than that of the pin. The upper end of the pin 177 has a cap 185which is seated within an enlarged portion or recess 187 of the bore179. In the retracted position the pin 177 is seated well within therecess 187 so that no accidental tripping is possible. To trip thecircuit breaker the pin 177 is depressed by inserting a smallscrewdriver, or other small tool, into the recess. Moreover, theadjusting knob 137 may be rotated without affecting the position of thepin. I

In addition to the pin 177 the manual tripping means comprises aninclined surface 189 at the upper edge of the trip bar 83 aligned withthe inclined surface 189.

Upon depression of the pin 177 the conical or tapered side 183 engagesthe inclined surface 189 and rotates the trip bar 83 clockwise (FIG. 5)to trip the circuit breaker 3 as described above. Although the pin 177and the trip bar 83 are both disclosed as having inclined or bevelledsurfaces, it is understood that the device would be operable if one ofthe trip bar and pin were provided with inclined or bevelled surfaces.

Accordingly, the device of the present invention provides a new andnovel trip device for a circuit breaker which is of a more compact sizethan the previous trip devices of the same rating.

What is claimed is:

l. A circuit interrupter trip device comprising a circuit breaker havinga first insulating housing, a circuit breaker mechanism within thehousing and comprising separable contacts adapted to be-connected aspart of the distribution system, the circuit breaker mechanismcomprising a releasable member movable when released from a latchedposition to effect opening of the contacts, a stationary magneticstructure for eachconductor of the distribution system and comprising acoil and core assembly and an armature, a trip bar movable to a trippedposition to effect release of the releasable member and being biased inthe latched position, the housing having an opening therein, anadjusting knob accessible at the opening and being manually operable toadjust the trip characteristics of the trip means, the adjusting knobhaving a bore therethrough, a trip pin accessible at the bore and beingmanually movable between retracted and depressed positions with the tripbar, and the trip pin being biased in the retracted position and beingmovable to the depressed position to move said trip bar to the trippedposition.

2. The circuit interrupter trip device of claim 1 in which the magneticstructure and the trip bar are mounted within a second insulatinghousing, and the second insulating housing being mounted within the 7first insulating housing.

3. The circuit interrupter trip device of claim 2 in which the manuallyoperable trip pin extends through the second insulating housing.

4. The circuit interrupter trip device of claim 3 in which at least oneof the end portions of the trip pin and the edge surface of the trip baris tapered.

5. The circuit interrupter trip device of claim 4 'in which the endportion of the trip pin is tapered and aligned with an edge of the tripbar.

6. The circuit interrupter trip device of claim 5 in which the edgesurface of the trip bar is bevelled and aligned with the tapered endportion of the trip pin.

7. The circuit interrupter trip device of claim 6 inwhich the trip pinand trip bar are aligned.

1. A circuit interrupter trip device comprising a circuit breaker havinga first insulating housing, a circuit breaker mechanism within thehousing and comprising separable contacts adapted to be connected aspart of the distribution system, the circuit breaker mechanismcomprising a releasable member movable when released from a latchedposition to effect opening of the contacts, a stationary magneticstructure for each conductor of the distribution system and comprising acoil and core assembly and an armature, a trip bar movable to a trippedposition to effect release of the releasable member and being biased inthe latched position, the housing having an opening therein, anadjusting knob accessible at the opening and being manually operable toadjust the trip characteristics of the trip means, the adjusting knobhaving a bore therethrough, a trip pin accessible at the bore and beingmanually movable between retracted and depressed positions with the tripbar, and the trip pin being biased in the retracted position and beingmovable to the depressed position to move said trip bar to the trippedposition.
 2. The circuit interrupter trip device of claim 1 in which themagnetic structure and the trip bar are mounted within a secondinsulating housing, and the second insulating housing being mountedwithin the first insulating housing.
 3. The circuit interrupter tripdevice of claim 2 in which the manually operable trip pin extendsthrough the second insulating housing.
 4. The circuit interrupter tripdevice of claim 3 in which at least one of the end portions of the trippin and the edge surface of the trip bar is tapered.
 5. The circuitinterrupter trip device of claim 4 in which the end poRtion of the trippin is tapered and aligned with an edge of the trip bar.
 6. The circuitinterrupter trip device of claim 5 in which the edge surface of the tripbar is bevelled and aligned with the tapered end portion of the trippin.
 7. The circuit interrupter trip device of claim 6 in which the trippin and trip bar are aligned.